1. Field of the Invention
The present invention relates to an inkjet head used for an inkjet recording apparatus for ejecting ink onto a recording medium to perform printing.
2. Description of the Related Art
A certain inkjet head used for an inkjet recording apparatus for ejecting ink onto a recording medium to perform printing is constructed such that ink supplied from an ink tank to a manifold is distributed to plural pressure chambers, and pulse-like pressures are selectively applied to these plural pressure chambers so that ink is ejected from nozzles communicating with the pressure chambers. In such an inkjet head, a flow-path unit including pressure chambers, manifolds, nozzles and/or ink flowpaths for connecting these is constructed by laminating plural plates having openings and holes for forming the pressure chambers and the like. Further, an actuator unit for changing volumes of the pressure chambers to eject the ink from the nozzles is disposed on, among the plural plates, a cavity plate that defines the pressure chambers. Here, there is a case where for example, a piezoelectric sheet is used as the actuator unit, and in that case, the piezoelectric sheet is laminated on the cavity plate.
Plural plates constituting the flow-path unit and the actuator unit are generally bonded by adhesive and are laminated to each other. However, when two plates are bonded to each other, for example, in a case where the amount of the adhesive is large or the adhesive is unevenly applied, there is a fear that the surplus adhesive overflows from between the two plates. Then, there has been proposed to form an escape groove for escaping surplus adhesive in the outer peripheral part of a plate along the outer peripheral shape of the plate (see, for example, JP-A-2002-96477 (FIG. 4)).